The measurement of metals by diffusive gradients in thin films (DGT) at sediment/water interface (SWI) of bay and remobilization assessment

The fine-scale profile (concentration/flux) of 14 metals at sediment/water interface (SWI) of Yingkou bay was measured by passive sampler-DGT (diffusive gradients in thin films) probe and HR-ICP-MS instrument. Fe profile in sediment porewater indicated redox reactions, which was verified by peaks at -6.75, -7.75, -8.75 and -11.75 cm. Mn profile in sediment porewater indicated redox-sensitive character with the continuous increase in profile from -3.75 to -5.75 cm, and the subsequent peaks at -6.25, -8.25, -9.75 and -11.25 cm. Both Fe and Mn profiles indicated low values at -10.25 cm, which was due to the formation of pyrite and the adsorption of Mn on it. The co-occurrence of some peaks and broad feature near peaks of trace metals and Fe/Mn at same depths of profiles indicated coupled geochemical process and co-remobilization. The diffusive fluxes of metals across SWI were also calculated and investigated.